In residential homes and commercial buildings, hot water is supplied from a water storage tank which stores a relatively large quantity of water. The size of the water storage tank is commensurate with the size of the home or building in which it is placed. Even small residential homes will have a water storage tank containing at least 20 or more gallons of water. Because the water storage tank operates under pressure once a leak develops, it takes only a relatively short time period for a substantial volume of water to escape from the tank into the surrounding area of the residential home or building. This can result in substantial flooding and damage particularly in those instances where the water storage tank or appliance is not located near a floor drain or is located on a floor above ground level.
Eventually, all water storage tanks leak. This is primarily the result of corrosion in the substructure of the tank or through the tank wall from minerals present in hard water. Corrosion on the inside of the tank is not visible outside the tank until the tank leaks at which time it is, in general, too late to take corrective action unless the leak is immediately located and proper action taken to close the water valves to the tank.